As far as I am aware Mohammed Asad was an Austrian Jew who reverted to Al-Islaam.
Guy Eaton is the author of such books as King of the Castle which are full of perrenialist (sp) beliefs, or the false, baatil belief that it doesn't matter which path one takes to Jannah, as they all lead to the Allaah whether it be through al-Islaam, Hinduism, Judaism etc etc.